Electronically commutated DC motor comprising a bridge circuit

Abstract

An electronically commutated DC motor comprises a stator comprising at least one stator winding (22, 24, 26), a rotor (28) electromagnetically interacting with the stator, a positive and a negative DC voltage line (76, 78) for supplying power to the motor (20), in particular from a battery (77), a full bridge circuit (74) for controlling the current in the at least one stator winding (22, 24, 26), which full bridge circuit (74) comprises a plurality of bridge arms that each comprise an upper bridge transistor (66, 80, 86) for controlling the current from the positive DC voltage line (76) to an associated terminal (68; 82; 88) of that stator winding (22, 24, 26) as well as a lower bridge transistor (70, 84, 90) for controlling the current from the relevant terminal of the stator winding to the negative DC voltage line (78). The motor further comprises an arrangement for generating a plurality of rotor position signals, and an arrangement for controlling a predetermined bridge transistor by logical combination of rotor position signals associated therewith, there being provided, for logical combination of those rotor position signals, a control transistor (60) to whose base a first rotor position signal (H1) is conveyable and to whose emitter a second rotor position signal (H2) is conveyable, and whose collector signal serves to control the predetermined bridge transistor (66). A circuit comprising a half bridge is also described.

Description

CROSS REFERENCE[0001]This application is a section 371 of PCT / EPO3 / 03067, filed 25 Mar. 2003 and published 16 Oct. 2003 in the German language as WO 03-085808-A1. The international application claims priority from German application DE 102 15 895.9, filed 11 Apr. 2002, which is incorporated by reference.FIELD OF THE INVENTION[0002]The invention concerns an electronically commutated DC motor comprising a full bridge circuit.BACKGROUND[0003]In such a motor, a plurality of rotor position signals are generated, and the individual semiconductor switches of the full bridge circuit are controlled by combinations of those rotor position signals. If a first rotor position signal is designated H1 and a second signal H2, then (as an example) one semiconductor switch of the full bridge must be switched on when the one signal H1 has the value 1 and the other signal H2 has the value 0. On the other hand, a different semiconductor switch of the full bridge must be switched on, for example, when H2...

AI Technical Summary

Benefits of technology

[0007]According to the invention, this object is achieved by providing a control transistor serving to logically combine the rotor position signals, a first rotor position signal being applied to the base of the control transistor, a second rotor position signal being applied to the emitter, and the collector signal serving to control the current in an associated stator winding. The control transistor effects a logical combination of two rotor position signals in simple fashion and without separate signal inversion, can additionally serve as a level converter as necessary, and allows reciprocal locking of the upper and lower bridge transistors of a bridge arm. The circuit is simplified by way of the invention in such a way that the requisite circuit board can be manufactured easily and inexpensively even for small motors; and installation space is obtained, as applicable, for additional motor functions.

Problems solved by technology

This results in complex circuits having many components, making it difficult, in the context of small motors, to accommodate the circuit board in the motor housing, and raising the cost of manufacturing the circuit boards (and therefore the motors), since multi-layer circuit boards are required.

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